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Title: Harvest-related edge effects on prey availability and foraging of hooded warblers in a bottomland hardwood forest.

The effects of harvest-created canopy gaps in bottomland hardwood forests on arthropod abundance and, hence, the foraging ecology of birds are poorly understood. I predicted that arthropod abundance would be high near edges of group-selection harvest gaps and lower in the surrounding forest, and that male Hooded Warblers (Wilsonia citrina) foraging near gaps would find more prey per unit time than those foraging in the surrounding forest. In fact, arthropod abundance was greater >100 m from a gap edge than at 0-30 m or 30-100 m from an edge, due to their abundance on switchcane (Arundinaria gigantea); arthropods did not differ in abundance among distances from gaps on oaks (Quercus spp.) or red maple (Acer rubrum). Similarly, Hooded Warbler foraging attack rates were not higher near gap edges: when foraging for fledglings, attack rate did not differ among distances from gaps, but when foraging for themselves, attack rates actually were lower 0-30 m from gap edges than 30-100 m or >100 m from a gap edge. Foraging attack rate was positively associated with arthropod abundance. Hooded Warblers apparently encountered fewer prey and presumably foraged less efficiently where arthropods were least abundant, i.e., near gaps. That attack rates among birds foragingmore » for fledglings were not affected by distance from gap (and hence arthropod abundance) suggests that prey availability may not be limiting at any location across the forest, despite the depressing effects of gaps on arthropod abundance.« less
Authors:
Publication Date:
OSTI Identifier:
859202
Report Number(s):
na
05-15-P; TRN: US200710%%78
DOE Contract Number:
AI09-00SR22188
Resource Type:
Journal Article
Resource Relation:
Journal Name: The Condor; Journal Volume: 107; Conference: na
Research Org:
USDA Forest Service, Savannah River, New Ellenton, SC
Sponsoring Org:
USDOE - Office of Environmental Management (EM)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; ABUNDANCE; ARTHROPODS; AVAILABILITY; BIRDS; ECOLOGY; FORESTS; MALES; MAPLES Arthropod; bottomland hardwoods; canopy gap; foraging; Hooded Warbler; timber harvest; Wilsonia citrina